按时间戳分钟查询postgres

Question

我想知道如何通过查询进行分组，我需要在我的数据库中对同一分钟的所有数据进行分组以对所有数据进行求和。

ws_controller_hist=>  SELECT timestamp, type, medium from default_dataset where type like 'status_devices' and timestamp> current_timestamp - interval '60 minutes' and organization_id = '9fc02db4-c3df-4890-93ac-8dd575ca5638' order by timestamp asc;

       timestamp        |      type      | medium
------------------------+----------------+--------
 2017-12-17 12:44:00+00 | status_devices | {1,0}
 2017-12-17 12:44:00+00 | status_devices | {1,0}
 2017-12-17 12:44:00+00 | status_devices | {1,0}
 2017-12-17 12:44:01+00 | status_devices | {1,0}
 2017-12-17 12:44:01+00 | status_devices | {1,0}
 2017-12-17 12:44:10+00 | status_devices | {0,1}
 2017-12-17 12:44:10+00 | status_devices | {0,1}

做这个查询

ws_controller_hist=>  SELECT timestamp, type, sum(medium[1]) from default_dataset where type like 'status_devices' and timestamp> current_timestamp - interval '60 minutes' and organization_id = '9fc02db4-c3df-4890-93ac-8dd575ca5638' group by timestamp, type order by timestamp asc;

       timestamp        |      type      | sum
------------------------+----------------+-----
 2017-12-17 12:44:00+00 | status_devices |   3
 2017-12-17 12:44:01+00 | status_devices |   2
 2017-12-17 12:44:10+00 | status_devices |   0

我想得到5个总和，这是分钟44中的总数可以理解的吗？

Answer 1

我想你想要date_trunc()：

select date_trunc('minute', timestamp) as timestamp_min, type, 
       sum(medium[1])
from default_dataset
where type like 'status_devices' and
      timestamp > current_timestamp - interval '60 minutes' and
      organization_id = '9fc02db4-c3df-4890-93ac-8dd575ca5638'
group by timestamp_min, type
order by timestamp_min asc;